Dentifrice compositions containing insoluble salts of amino alkylene phosphoric acids

ABSTRACT

DENTIFRICE COMPOSTITON CONTAINING AS THE PRIMARY POLISHING AGENT A SUBSTANITIALLY WATER-INSOLUBLE SALT OF AN AMINO-ALKYLENE PHOSPHONIC ACID SUCH AS THE CALCIUM SALT OF AN AMINO TRI(ALKLIDENE PHOSPHONIC ACID) HAVING THE FORMULA, E.G.   N-(CH2-PO3H2)3

United States Patent 3,642,979 DENTIFRICE COMPOSITIONS CONTAINING IN-SOLUBLE SALTS OF AMINO ALKYLENE PHOS- PHORIC ACIDS Riyad R. Irani,Mentor, Ohio, assignor to Monsanto Company, St. Louis, M0.

N0 Drawing. Filed Feb. 6, 1969, Ser. No. 797,225 Claims priority,application Trinidad and Tobago, Mar. 9, 1968, 22/68 Int. Cl. A61r 7/16US. Cl. 424--54 3 Claims ABSTRACT OF THE DISCLOSURE Dentifricecompositions containing as the primary polishing agent a substantiallywater-insoluble salt of an amino-alkylene phosphonic acid such as thecalcium salt of an amino tri(alkylidene phosphonic acid) having theformula, e.g.

The present invention generally relates to dentifrice compositionscontaining novel polishing agents and more particularly relates toimproved dentifrice compositions containing such novel polishing agentsalong with stannous tin and fluoride in an ionized state. The presentinvention further relates to dentifrice compositions containing, as anabrasive therein, a novel ingredient which is compatible with theaforementioned stannous tin and fluoride ions which also may be presentin said compositions. The present invention is more specificallydirected to dentifrice compositions containing the aforementioned novelingredient which has a polishing and cleansing effect and is furthercharacterized, when said composition is used in oral hygiene, fromdeleterious abrasive or scratching action of tooth enamel and dentin.

In the field of oral hygiene, a satisfactory dentifrice should have acosmetic effect on the teeth whereby the daily use of said dentifricekeeps said teeth in an essentially stain-free (or white appearing)state. Such a dentifrice should also have a functional effect on theteeth and mouth, keeping them clean and free from food debris, therebyaiding the prevention of tooth decay. In order to achieve theseaforementioned end results, it is generally necessary to brush the teethwith a dentifrice composition containing a cleaning agent which isgenerally referred to in the art as an abrasive. The main purpose ofthis cleaning agent is to aid in the removal from the tooth surface oftightly, adherent pellicle film which in many persons contains pigmentswhich color said film (and thus the teeth) brown or yellow. Furthermore,this cleaning agent should remove this pellicle film with a minimum ofabrasion of the underlying tooth material. The tooth surface is coveredwith what is commonly known as enamel which covers much of the exposedtooth surface and is a relatively hard material which, generallyspeaking, is not materially affected by polishing agents. However, thesofter dentin, which may be exposed by receding gums, is a major problemand concern in selecting an ideal or appropriate cleaning agent. Thusthe agent selected must be one which effects the maximum removal of thepellicle film with the minimum abrasion of the dentin.

In addition to the function of the dentifrice in maintaining oralhygiene or cleanliness, there is also merit in including an ingredientwhich acts specifically to reduce tooth decay. In the past years,extensive laboratory and field experimentation has been stimulated bythe discovery of the beneficial effect of fluoride in drinking water ortopically applied to the tooth surface and 3,642,979 Patented Feb. 15,1972 "ice has subsequently led to the development of dentifricescontaining stannous fluoride and, more recently, sodiummonofluorophosphate. The successful effect of these fluoride (andstannous ions in the case of stannous fluoride)- containing dentifrices(which include, respectively, P and P0 1 ions in solution) in reducingthe incidence of caries has been well established by statisticalevidence. Such effectiveness is substantiated as exemplified by the bodyof scientific literature hereinafter set forth, and which supports theconclusion that the use of dentifrices containing a source of fluorideions (which term, as used herein, includes F, PO F and other fluorideion complexes) reduces the rate at which dental caries are formed; noteI. C. Muhler et al., Journal of Dental Research, vol. 33, page 606(1954); J. C. Muhler et al., Journal of the American Dental Association,vol. 50, page 163 (1955); J. C. Muhler et al., Journal of DentalResearch, vol. 35, page 49 (1956); and W. A. Jordon et al., Journal ofthe American Dental Association, vol. 54, page 589 (1957). It is alsothe opinion of some scientists that the presence of stannous ions withfluoride ions gives a more effective paste than fluoride alone; note JC. Muhler et al., Journal of American Dental Association, vol. 51, page556 (1955).

One major problem in the manufacture and widespread distribution of suchdentifrices is to maintain the fluoride ions (and stannous ions whenusing, for example, Sn'F over a period of. many months, in substantiallyan available form, and in such form thus be available for the treatmentof the teeth in a manner heretofore set forth. The main reason for thisreduction of availability of such ions is the reaction thereof with thecleaning agent, i.e. the polishing agent or abrasive ingredient, to formcomplexes which are non-reactive with the tooth surface.

While the prior art has generally recognized this latter problem ofmaintaining the fluoride ions (and stannous ions) in available form whenincorporated in a dentifrice composition, there has also been asubstantial need in the dentifrice art for the provision of a dentifricewhich contains a cleaning agent or abrasive material having a low dentinabrasion value and which abrasive is also compatible, i.e. does notdetrimentally react with F', PC 1 Sn++, with said dentifrice compositioncontaining the ionic anti-caries agent such as stannous fluoride orsodium monofluorophosphate.

Accordingly, it is one object of the present invention to provide adentifrice composition containing a novel polishing agent.

It is another object of the present invention to provide a dentifricecontaining fluoride ions (and stannous ions, if using SnF which do notreact detrimentally with the abrasive or cleaning agent and thus remainavailable for treatment of the tooth surface on use.

It is another object of the present invention to provide an abrasivematerial which is effective in removing pellicle films from the teethand which causes a minimum of abrasion to the dentin.

Further objects and advantages of the present invention will becomeapparent from the subsequent description and the appended claims.

In general, the present invention provides a dentifrice compositioncontaining ingredients usually employed in toothpowders or toothpastesand an abrasive or polishing agent comprising a substantiallywater-insoluble salt of an aminoalkylene phosphonic acid, which may beused as the sole polishing agent or in combination with minor amounts ofother dental abrasives or polishing agents such as dicalciumorthophosphate dihydrate, insoluble sodium metaphosphate, dentalabrasive grade of calcium pyrophosphate and the like, and mixturesthereof.

A particularly preferred class of substantially Waterinsoluble metalsalts of amino-alkylene phosphonic acids which may be employed in thedentifrice compositions are the substantially water-insoluble salts ofacids of the following formula:

wherein A is a carbon atoms, A or wherein n is an integer from 1 to(preferably 3-10); Z isHorAandZ'isAor wherein m is an integer from 1 to20 (preferably 3-10); Y and Y in the above formula represent straight orbranched chain lower aliphatic radicals, preferably 1 to 4 carbon atomsand hydrogen, which are unsubstituted or which may be substituted withgroups such as hydroxyl, halide, alkoxy, sulfonyl, carboxyl, amide oramino groups; and either R or R have at least one group corresponding toA. The most suitable salts of these acids for use in the dentifricecompositions of this invention are the calcium, barium, magnesium, zincand/or aluminum salts, and these include partial salts, that is, thosepartial salts in which one or more of the hydrogen atoms of the (OH)groups in the acids of the above formula have not been replaced by suchmetal atoms, but are still sufficiently insoluble in water to haveutility as polishing agents in the dentifrice compositions, and alsoinclude salts in which one or more hydrogen atoms of the (OH) groups inthe above formula have been replaced by sodium or ammonium ions, but arestill sufficiently insoluble in water to have utility as polishingagents in the dentifrice compositions. Also included are hydrates ofsuch salts. Acids of the above structural formula may be prepared by theprocedures described in US. Pat. No. 3,298,956, issued to Riyad R. Iraniand Kurt Moedritzer on Jan. 17, 1967.

Some specific examples of the aforedescribed general class ofsubstantially water-insoluble salts of amino-alkylene phosphonic acidsare the following:

(1) Calcium or magnesium salts of aminotrimethylene phosphonicacidspecifically CaH N(CH PO 3 7H O;

MgH N (OH PO 3 -XH O where X may vary from 1 to 7;

Ca H N( CH PO 3 XH O where X may vary from 4 to 10; and Mg H- 'N(CH PO(2) Calcium or magnesium salts of hexamethylene diaminetetra(methylphosphonic acid)- 4 Specifically Ca H [CH PO N-(CH N[CH POand Mg H [CH PO N(CH N[CH 'PO and hydrates thereof; and

(3) Calcium or magnesium salts of amino di(methylphosphonic acid)(butylidene phosphonic acid and hydrates thereof.

Another embodiment of the present invention provides a dentifricecomposition containing (a) one or more of the aforedescribedsubstantially water-insoluble salts of the aminoalkylene phosphonicacids; and (b) a watersoluble, innocuous (as hereinafter defined),fluoride salt such as Water-soluble, fluorine-containing organic salts;Water-soluble fluorine-containing inorganic salts, and mixtures thereof.If desired, a Water-soluble, innocuous, stannous tin salt of a mineralacid can be added to the abovedescribed composition in order to providestannous ions (if SnF is not the fluoride salt) or an excess of stannousions (even if SnF is used). It is to be noted that the fluoridesincluded under (b) and said tin salt can represent either the samecompound, for example, stannous fluoride, or different compounds, forexample, (b) can be sodium fluoride and such additional stannous tinsalt can be stannous fluoride.

The adjective innocuous, as used herein in regard to fluoride andstannous compounds means a compound which is substantially non-toxic inthe proportions used, or not highly colored, or otherwise objectionablefor use in a dentifrice composition.

The substantially water-soluble salts of amino-alkylene phosphonic acidshave a satisfactory degree of polishing and cleaning action and at thesame time they are sufficiently non-abrasive to minimize scratching orother deleterious effects on the enamel or cementum of the teeth. Suchsalts usually have a dentin abrasion value, as hereinafter defined, ofless than 500, usually from 200 to about 350. A polishing agent havingthis low dentin abrasion value, is still effective in its cleaningaction when applied in oral hygiene but, on the other hand, it does notdetrimentally abrade the tooth surface. Dicalcium orthophosphatedihydrate, a commonly used polishing agent, in dentifrices, usually hasa dentin abrasion value of about 250 350.

The dentin abrasion value is a relative number indicating the degree ofabrasiveness of a material. The procedure for the evaluation of thisabrasiveness is the method of Grabenstetter et al. described in theJournal of Dental Research, Vol, 17, No. 6, November-December 1958, pp.1060-1068; note also US. Pat. No. 2,876,168. Briefly, the cleaning agentor abrasive is determined to have a certain dentin abrasion value afterit has been utilized in the mechanical brushing of radioactive dentinfrom extracted human teeth.

In general the aforementioned substantially water-insoluble salts ofamine alkylene phosphonic acids (as polishing agents) constitute fromabout 0.5% to about 96% by weight of the total Weight of the dentifricecomposition. When such polishing agents are being utilized in adentifrice composition such as toothpaste, it is preferred that they bepresent in an amount of from about 20% to about 60% by weight of thetotal weight of the dentifrice composition. On the other hand, when itis desired to prepare a toothpowder, it is preferred that such polishingagents be present in an amount of from about 60% to about 96% by weightbased on the total weight of the dentifrice composition.

It is preferred that the polishing agents of this invention be in solid,particulate form. If they have first been prepared in lumps or sizeableparticles, they can be reduced to the desired particle size byconventional grinding methods such as impact, ball, and tube mills. Ifthe polishing agents are initially prepared in the form of solidparticles having the desired size distribution, a grinding step is notnecessary.

It is preferred that the polishing agents of this invention be composedof solid particles substantially all of which have a diameter of lessthan 50 microns. Larger particles tend to feel gritty in the mouth andto stick between teeth. The mean diameter of the particles of thepolishing agents is desirably between about microns to about 40 micronsand preferably from about 5 microns to about 20 microns, for optimumperformance, Preferably not more than about weight percent of theparticles have a diameter of less than about 1 micron. Finer particlesare relatively ineffective in cleaning teeth, and therefore the fractionof flner particles should be limited. By particle is meant aggregates aswell as individual particles. It might be supposed that only particleswith sharp edges and corners would be effective in removing pelliclefilm from the teeth. However, it has been discovered that relativelyspherical particles and aggregates of relatively spherical particlesalso serve as effective cleaning agents. (The particle diametersreferred to herein were determined by microscopic measurements using acalibrated eyepiece.)

In the case of fluoride-containing dentifrice compositions the fluorideions are usually incorporated in the composition in the form of stannousfluoride which also provides stannous tin ions (in solution). However,when it is desirable to control the ratio of stannous ions to fluorideions, such control being suggested by the prior art (for example, noteUS. Pat. 2,946,725), in order to provide more stannous ions than thefluoride ions available in stannous fluoride, the stannous tin can besupplied in the form of a water-soluble, stannous tin salt of a mineralacid (hereinafter referred to as the other stannous salt). As examplesof such other stannous tin salts, there may be mentioned, for exemplarypurposes only, compounds such as stannous chloride, stannous sulfate,stannous nitrate, monochlorostannous fluoride (Sn ClF and SnClF),fluorostannitesfor example, KSnF hexa-fluorozireonate-for example, SnZrFand the like.

The other stannous salt content of the dentifrice composition, asexpressed in parts per million of the stannous ions, should be in therange of from about 2,000 to about 15,000 parts of stannous ion permillion parts of the total weight of such dentifrice composition. It ispreferred that the stannous ion be present, when used in suchcomposition, in the range of from about 6,000 to about 11,000 parts permillion stannous tin. Especially effective dentifrices are usuallyobtained when the minimum total stannous tin content is about 6,000parts per million to about 8,000 parts per million. Experimentalevidence indicates that if the stannous tin content is below the lowerlimit of 2,000 parts per million, the dentifrice compositions tend tolose some of their effectiveness in regard to caries prevention.Furthermore, when the tin content in above about 15,000 parts permillion, no further solubility reduction of the tooth enamel isapparent.

Fluoride ions may be incorporated in the dentifrice compositions of thisinvention by the incorporation of any one or mixtures of water-soluble,innocuous, fluorinecontaining organic or inorganic salts. Manywater-soluble inorganic fluoride salts are suitable sources of fluorideions, i.e. F- or complex fluoride ions, e.g. PO F Among these saltsthere may be mentioned, for exemplary purposes only, lnF PbGg, FeF LiF,CaF NaF, KF, NH F, PdF and the like. It should also be understood thatthe term fluoride salts, as used herein, is also intended to includecomplex water-soluble fluoride-containing salts such asfluorophosphates, e.g. Na PO F, fluorosilicates, e.g. Na SiF and H SiFfluorozirconates, e.g. CaZrF Na ZrF K ZnF fluoroborates, e.g. NaBF andfluorotitanates. Mixtures of the aforementioned fluoride salts can alsobe used herein,

The fluoride ion, which term includes, for example, both F" and PO F orother complex ions, may also be supplied to the dentifrice compositionby means of an organic fluoride which is soluble in water or at leastwhich dissociates to give fluoride ions when in contact with water. Asexamples of organic fluorides, there may be mentioned the organichydrofluorides, i.e. amine fluorides like mono-, di-, andtri-ethanolamine hydrofluorides, such as those compounds disclosed inCanadian Pat. 543,066 issued on July 2, 1957, to Philip Zutovern et al.and which patent is incorporated herein by reference. These compoundsmay also be named as the corresponding ethanol-ammonium fluorides suchas triethanolammonium fluoride. Other useful organic fluorides andhydrofluorides are disclosed in a publication by H. R. Muhlemann et al.in Helvetica Odonlotogica, vol. I, No. 2, page 23, 1957, whichpublication is also incorporated herein by reference.

.The quantity of the water-soluble fluoride compounds, which may be usedin combination with stannous tin in the dentifrice compositions of thisinvention, should be an amount equivalent to provide at least 25 partsof fluoride ions per million parts of the total dentifrice composition.It has been fou sl that extremely large amounts of fluoride ions do notappreciably enhance the desirable properties of the dentifrice and may,under certain circumstances, produce toxic effects. Accordingly, it isdesirable that the dentifrices of the present invention contain not morethan a total of about 4,000 5,000 parts of ionized and unionizedfluorine per million parts of dentifrice composition and preferably notmore than 3,000 p.p.m. However, a level of from about 1000 to about10,000 p.p.m. fluoride ions can be used if desired without toxiceffects. A preferred level of fluoride ions is from about 500 p.p.m. toabout 2,000 per million parts of the total dentifrice composition. (Itis to be noted that when the fluoride salt is, for example, sodiummonofluorophosphate, Na PO F, it has previously been found that it isnot necessary to utilize a stannous tin salt, i.e. to supply Sn++, inorder to obtain an effective anticaries dentifrice.

While the foregoing description has been directed primarily to variousways of incorporating stannous tin ions and fluoride ions in adentifrice composition, it is also possible, as previously mentioned, touse stannous fluoride per se as the source of stannous and fluorideions. Stannous fluoride generally is used in amounts less than 50,000parts per million by Weight, based on the total weight of the dentifricecomposition. It is preferred that this salt, i.e. SnF level be less than25,000 p.p.m. and between the range of from about 200 p.p.m. and 2,000p.p.m. by weight.

Generally the major portion of ingredients (i.e. in excess of 50% byweight) of a dentifrice composition comprises the polishing agent or thepolishing agent and fluoride compound.

It is desirable that the pH of the dentifrice composition of thisinvention lie between about 5 and about 8, preferably from about 5 toabout 7, and more desirably from about 5.5 to about 6.5. When the pH ofthe dentifrice composition is above about pH 8, there results a loss ofmetal ions, i.e. stannous ions, available for reaction with enamel and,in addition, certain flavoring substances, especially esters,deteriorate rapidly. At a pH below about 4 or 5, there is produced anastringent paste which is generally objectionable to most people. Inaddition, the lower pH also accelerates the hydrolysis of certain of thesudsing agents normally used in dentifrices thereby producing anunpleasnat fatty acid taste and reducing the amount of sudsing obtained.Furthermore, when the pH values are below 4 or 5, there is a tendency tocause corrosion of metal tubes in which the paste is stored and alsothere is a tendency to hydrolyze other ingredients in the dentifricemixture. It should be noted that when referring to pH herein, the pHvalues specified are those obtained by measuring the pH of thesupernatant liquid resulting by forming a slurry of 1 part by weight ofdentifrice and 3 parts by weight distilled water.

In addition to the aforementioned ingredients utilized in the dentifricecompositions of the present invention, such compositions may alsoconventionally contain foaming or sudsing agents although the use ofthese agents is not critical in the practice of the present invention.Any of the commonly used foaming or sudsing agents can be used if theyare reasonably stable non-toxic and foam or form suds within the pHrange of the dentifrice of this invention. As examples of suitablesudsing agents, there may be mentioned water soluble alkyl and alkylether sulfates and sulfonates having alkyl groups of from about 8 toabout 18 carbon atoms, water soluble salts of sulfonates, monoglyceridesof fatty acids having from about 10 to about 18 carbon atoms,water-soluble salts of sulfated fatty alcohols having from about 10 toabout 18 carbon atoms, salts of fatty acid amides of taurines such assodium-N-methyl-N-palmitoyl tauride, salts of fatty acid esters ofisethionic acid, and salts of substantially saturated aliphatic acylamides of saturated aliphatic monoaminocarboxylic acids having fromabout 2 to about 6 carbon atoms and in which the acyl radical containsfrom about 12 to about -16 carbon atoms, such as sodium N-lauroylsarcoside. It is also to be understood that mixtures of two or moresudsing agents can be utilized herein. These sudsing agents aregenerally used in an amount of from about 0.5% to about 5.0% by weight,based on the weight of the dentifrice composition.

In addition to the aforementioned ingredients, it may also be necessary,in order to obtain the proper consistency in certain toothpastes, to addvarious thickening materials. As examples of such thickening materialsthere may be mentioned water-soluble salts of cellulose ethers such assodium carboxymethylcellulose and sodium carboxymethyl hydroxyethylcellulose. Natural gums such as gum karaya, gum arabic, and gumtragacanth also can be used as thickeners but may tend to causeundesirable odors or flavors in some formulations. In addition to theabove mentioned thickeners, colloidal magnesium aluminum silicate orfinely divided silica (such as silica areogels or fume silica) can alsobe used as a part of the thickening agent for improvement in texture.These thickening agents are generally used in an amount of from about0.5% to about 5.0% by weight, based on the weight of a toothpastedentifrice composition.

The dentifrice compositions of the present invention may also include,in addition to any of the aforementioned ingredients, suitablehumectants, such as glycerine, sorbitol and other polyhydric alcohols.These humectants are generally used in an amount of from 0.5% to about35% of the dentifrice composition.

The dentifrice compositions may also additionally contain small amountsof 'flavorings such as oil of wintergreen, oil of peppermint, oil ofSpearmint, oil of sassafras, and oil of anise. Small amounts ofsweetening agents such as saccharin, dextrose, levulose, and sodiumcyclamate are also conventionally added to dentifrices.

In toothpaste formulations, water is generally used as a base and ispresent in an amount of from about 5% to about 60% by weight, based onthe total weight of the composition.

Finally, if one further desires, a suitable coloring agent may be addedto said dentifrice composition in order to enhance its aesthetic effect.

All of the aforementioned ingredients which are utilized in the presentinvention dentifrice compositions may be incorporated therein in anyorder, in order to formulate said compositions.

A further understanding of the novel and unique compositions of thepresent invention will be obtained from the following specific exampleswhich are intended to illustrate the invention, but not to limit thescope thereof, parts and percentages being by weight unless otherwisespecified.

EXAMPLE I A toothpaste was prepared by first grinding 800 grams of solidparticles of the dicalcium salt of amino-trimethylene phosphonic acid asthe heptahydrate, that is, Ca H N(CH PO -7H O, until at least of theparticles were of a size within the range of about 1 to about 20microns. The resulting material was the polishing agent. Next a solutionwas prepared by mixing together 306 grams of glycerine, 306 grams ofwater and 1 gram of saccharin, which solution was heated to 90 C. "whilethoroughly mixing the ingredients. This solution was then added withthorough mixing to the aforementioned polishing agent, and to theresultant mixture was added a solution consisting of (a) 60 millilitersof water, (b) 28 grams of sodium laurylsulfate, (c) 60 grams ofglycerine and (d) 10 grams of mint flavoring. The resulting pastemixture was thoroughly mixed together until a toothpaste consistency wasachieved. This paste which had a pH of about 6 was a satisfactorycleaning agent for teeth when used in the customary way with atoothbrush, and had a dentin abrasion value of about 300.

EXAMPLE II A toothpaste Was prepared using the same ingredients andprocedure described in Example I with the exception that a slurry of11.8 grams of stannous fluoride in 50 milliliters of water was usedinstead of the 60 milliliters of water referred to under (a) in ExampleI. The resulting paste was stored in a closed bottle for 30 days at 20C., after which a sample was withdrawn from the bottle and analyzed forpercent available fluoride and stannous ions to ascertain thecompatibility, as hereinafter defined, of the polishing agent in thepresence of fluoride and stannous tin ions. The available fluoride andstannous tin is that fluoride and tin which have not been hydrolyzed oroxidized and which are available for absorption by the enamel of a toothsurface.

The aforementioned fluoride and stannous ion compatibility wasdetermined in the following manner. Approximately 10 grams of thetoothpaste were shaken with milliliters of distilled water for one hourat a setting of 4 (the range is from 1 to 10 with 10 being the fastest)on an automatic shaker, commercially available under the trade nameBurrell shaker. The resulting slurry was then centrifuged for 15 minutesat the maximum speed in a high speed centrifuge, commercially availableunder the trade name Servell centrifuge. A 25 milliliter portion of theclear supernatant liquid was transferred to a small bottle containing 4grams of tricalcium phosphate. The bottle was capped and placed in theabove-described Burrell shaker and shaken for 20 minutes at a setting of4. The resultant tricalcium phosphate sample treated with the slurrymade from the toothpaste formulation was then transferred to a Buchnerfunnel, filtered and washed with three 15 milliliter portions of waterand then washed with three 15 milliliter portions of acetone and thenfinally dried in air. The sample was then analyzed for fluorine andstannous ion content by emission spectroscopy. The percent ofcompatibility, that is, the amount of fluoride and stannous ionsremaining after a period of time when in contact with the aforementionedabrasives is determined in accordance with the following formula:

Compatibility concontration of stannous or fluoride ions after testsconcentration of stannous or fluoride ions before tests As a result ofthe above-described analytical procedure it was determined that thetoothpaste after 30 days storage had a fluoride compatibility of 33.5%and stannous ion compatibility of 27.2%. By way of contrast a comparabletoothpaste prepared by using calcium pyrophosphate (Ca P O as theabrasive or polishing agent had a fluoride compatibility of about 15.9%and a stannous ion compatibility of about 16%.

It can readily be seen then, from the aforementioned results, that thecalcium salt of amino alkylenephosphonic acid not only has a low dentinabrasion value but is quite compatible with a dentifrice compositioncontaining fluoride and stannous ions in such a composition during anextended storage period.

EXAMPLE III The aforementioned Example II of the present invention wasrepeated with the exception that in place of the slurry of stannousfluoride dissolved in water, there was substituted a slurry of a mixtureof stannous nitrate and sodium fluoride dissolved in water. Such mixturewas used in an amount to provide the same stannous and fluoride ionconcentrations as obtained in Example II. The results obtained weresubstantially the same as those results set forth in Example II. Thus,the use of separate and different compounds to provide stannous andfluoride ions to the dentifrice composition yields the same abrasivecompatibility results as contrasted to the utilization of stannousfluoride.

EXAMPLE IV The aforementioned Example 11 of the present invention wasagain repeated with the exception that in place of the slurry ofstannous fluoride dissolved in Water, there was substituted a mixture ofsodium monofiuorophosphate dissolved in water. The amount of such sodiummonofluorophosphate used was sufficient to provide approximately 2,000parts per million of fluoride ions, i.e. PO P The results obtained weresubstantially the same as those results set forth in Example II withreference to the available fluoride in a toothpaste mixture stored overa period of approximately 30 days. From these results showing thecompatibility of sodium monofiuorophosphate with the calcium salt ofamino alkylenephosphonic acid, it can readily be seen that this abrasivematerial is compatible with a Wide variety of fluoride containing watersoluble salts.

EXAMPLE V A toothpowder was prepared by thoroughly mixing together 96grams of the polishing agent described in Example I togeher with 1.5grams of powdered sodium lauryl sulfate, 1.2 grams of oil of peppermint,1 gram of sodium citrate and 0.3 gram of saccharin. A slurry of theresulting toothpowder had a pH of about 6, and a dentin abrasion valueof about 300.

What is claimed is:

1. A toothpaste composition comprising as the primary polishing agent amember selected from the group consisting of (1) a substantiallyWater-insoluble salt selected from the group consisting of a calciumsalt, magnesium 10 salt, zinc salt, aluminum salts and mixtures thereofof an ammo alkylene phosphonic acid having the formula:

N-A Rz wherein A is a Y o -di =(ori)2 group, R is selected from thegroup consisting of H, an aliphatic radical containing from 1 to 4carbon atoms, and A, and R is selected from the group consisting of H,an aliphatic radical containing from 1 to 4 carbon atoms,

wherein n is an integer from 3 to 10; Z is selected from the groupconsisting of H and A, and Z is selected from the group consisting of Aand I I o-N o1 =(0H),

Y Z In Y wherein m is an integer from 3 to 10; Y and Y' are selectedfrom the group consisting of straight chain aliphatic radicals havingfrom 1 to 4 carbon atoms, branched chain aliphatic radicals having 1 to4 carbon atoms and H, and (2) a hydrate of said salts, the particles ofsaid polishing agent having a mean diameter of from about 5 microns toabout 40 microns, said polishing agent having a dentin abrasion value ofless than 500, and said polishing agent being present in said dentifricecomposition in an amount of from about 20 weight percent to about weightpercent, based on the weight of the dentifrice composition.

2. A dentifrice composition as set forth in claim 1 wherein thecomposition is a toothpaste.

3. A dentifrice composition as set forth in claim 1 wherein saidpolishing agent is a salt selected from the group consisting of acalcium salt of amino(trimethylene phosphonic) acid and a hydratethereof.

References Cited UNITED STATES PATENTS 3,029,191 4/1962 King 424-523,227,618 1/ 1966 Manahan et al. 424-52 3,442,604 5/1969 Smith et a1424-57 RICHARD L. HUFF, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 6 PATENT NO. 3,6r2,979

DATED February 15, 97

|NVENTOR(S) Riyad R. Irani It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column t, line 33, "water-soluble" should be corrected to readwater-insoluble Signed and Scaled this Twenty-first Day of March 1978[SEAL] Arrest.-

i. RUTH C. MASON LUTRELLE F. PARKER Arresting Officer ActingCommissioner of Patents and Trademarks

